| 氮添加对生长季寒温带针叶林土壤有效氮和酸化的影响 |
| 摘要点击 1728 全文点击 1123 投稿时间：2014-05-18 修订日期：2014-07-18 |
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| 中文关键词 氮沉降 森林土壤 氮循环 无机氮 土壤酸化 |
| 英文关键词 N deposition forest soil N cycle inorganic nitrogen soil acidification |
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| 中文摘要 |
| 基于低剂量、多形态的N添加控制实验，以大兴安岭寒温带针叶林为研究对象，通过长期持续的原位增N处理，测定了2010年、2012年和2013年生长季初期（5月）和生长旺季（8月）0~10 cm土壤有效氮（NH4+-N和NO3--N）含量以及土壤pH值. 结果表明，生长季初期和生长旺季土壤有效氮均以NH4+-N为主，NO3--N含量较低，其中NH4+-N含量占无机氮含量的96%以上. 随着增N时间的延长，同生长旺季相比，增N对生长季初期0~10 cm土壤NH4+-N影响较为明显，且主要受施N类型影响. 与此相反，生长旺季0~10 cm土壤NO3--N含量高于生长季初期. N输入对生长季初期和生长旺季土壤NO3--N影响较为明显，且低N处理更倾向于促进0~10 cm土壤NO3--N的富集. 随着时间的延长，土壤NH4+-N和NO3--N对增N的响应都由前期的不显著向后期的显著转变. 增N对生长季初期和生长旺季0~10 cm土壤pH值影响显著，其中低N处理的土壤和生长旺季阶段土壤pH值相对较低. 随着增N时间的延长，土壤pH值对增N的响应也由前期的不显著向后期的显著转变. 长期持续的增N处理已经使大兴安岭寒温带针叶林0~10 cm土壤产生了明显的酸化. |
| 英文摘要 |
| Based on a low-level and multi-form N addition control experiment, this study took cold-temperate coniferous forest in Daxing'an Ling as the research object. After long-term and continuous nitrogen addition in situ, the available nitrogen (NH4+-N & NO3--N) contents and pH values of the soil (0-10 cm) were measured in the early growing season (May) and the peak growing season (August) in 2010, 2012 and 2013. The results showed that, the available nitrogen in the early and peak growing seasons was mainly NH4+-N which accounted for over 96% of the inorganic nitrogen content, while the content of NO3--N was very low. With the time extension of nitrogen addition, the effects of nitrogen addition on the NH4+-N content in 0-10 cm soil were more obvious in the early growing season than that in the peak growing season, and the NH4+-N content was mainly affected by the type of nitrogen addition. On the contrary, the NO3--N content in 0-10 cm soil was higher in the peak growing season than that in the early growing season. The effect of N input was obvious on NO3--N content in both early and peak growing seasons, and low nitrogen treatment tended to promote the enrichment of NO3--N. As time went on, the response of NH4+-N and NO3--N content to N addition was changed from insignificant in the early stage to significant in the late stage. N addition had a significant impact on the pH value of the 0-10 cm soil in the early and peak growing seasons. The pH values of the soil with low nitrogen treatment and the soil in the peak growing season were relatively lower. With the extension of the nitrogen addition time, the response of pH value also turned from insignificant in the early stage to significant in the late stage. Because of the long-term and continuous nitrogen addition, the 0-10 cm soil in this cold-temperate coniferous forest was obviously acidified. |
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